* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    font-size: 16px;
  }
  body {
    position: relative;
    /* 禁止复制 */
    user-select: none;
    min-width: 375px;
  }
  a {
    text-decoration: none;
  }
  li {
    list-style: none;
  }
  header,
  main,
  footer {
    width: 100%;
  }
  /* header区域 */
  header {
    color: #fff;
    text-shadow: 1px 1.5px black;
    display: flex;
    justify-content: space-between;
    line-height: 49px;
    background: linear-gradient(to right, #4c8bff, #20d1fe);
  }
  header .nav-left,
  header .nav-right {
    margin: 0 1.2rem;
  }
  header .nav-right ul {
    display: flex;
  }
  header .nav-right ul li:nth-child(-n + 3) {
    margin: 0 1rem;
  }
  header a {
    color: #fff;
    text-shadow: 1px 1.5px #ccc;
}
  header a:hover{
    font-weight: bold;
  }
  .nav-left img {
    display: inline-block;
    vertical-align: middle;
    width: 50px;
  }
  /* footer区域 */
footer {
    position: absolute;
    bottom: 0;
    height: 51px;
    overflow: hidden;
    text-align: center;
    line-height: 51px;
    color: #fff;
    text-shadow: 1px 1.5px #ccc;
    background: linear-gradient(to right, #4c8bff, #20d1fe);
  }